HF The History of Photography 600pág

24 The prehistory of photography
Pl -t
been newly taken by the Duke of Bavaria: who, blandientefortuna , was gone on to
the late effects : There I found Keplar (sic), a man famous in the Sciences, as your
Lordship knowes, to whom I purpose to convey from hence one of your Books,
that he may see we have some of our own that can honour our King, as well as
he hath done with his Harmanica. In this mans study, I was much taken with the
draught of a Landskip on a piece of paper, methoughts masterly done: Whereof
enquiring the Author, he bewrayed with a smile it was himself, adding he had
done it non tanquam Pictor sed tanquam Mathematicus. This set me on fire: at last he
told me how. He hath a little black tent (of what stuffe is not much importing)
which he can suddenly set up where he will in a field, and it is convertible (like a
Wind-mill) to all quarters at pleasure, capable of[accommodating] not much more
than one man, as I conceive, and perhaps at no great ease ; exactly close and dark
save at one hole, about an inch and a half in the Diameter, to which he applies a
long perspective-trunke, with the convex glasse fitted to the said hole, and the
concave taken out at the other end, which extendeth to about the middle of this
erected Tent, through which the visible radiations of all the objects without are
intromitted, falling upon a paper, which is accommodated to receive them ; and so
he traceth them with his Pen in their natural appearance, turning his little Tent
round by degrees till he hath designed the whole aspect of the field : this I have
described to your Lordship, because I think there might be good use made of it for
Chorography [topographical drawings] : For otherwise, to make Landskips by it
were illiberall: though surely no Painter can do them so precisely.27
By 'perspective-trunke' Wotton meant Kepler's telescope, from which the concave
lens had been removed. Kepler's tent camera obscura, which is an intermediate form
between the darkened room and the box camera, was constructed rr3 years or more
before the ABBE NOLLET submitted his re-invention to the Academie Royale des
Sciences in 1733. 28
Kepler himself does not refer to the tent camera, but in his first book on Optical
Astronomy29 he mentions Porta's description of the room type and states that he
made some observations of the sun by this means in 1600. In his second book, on
dioptrics, 30 he discusses the optical laws involved in the camera obscura with lens.
Of special interest to photographers is Problem CV, p. 54, 'To depict with a
concave and convex lens upon paper visible objects larger than by a single convex,
but reversed', for this is the principle of the optical system employed in telephotography.
Kepler explains it with a figure showing the dispersion of the rays by a
concave lens after having passed through a convex lens. However, Kepler is not the
inventor of the telescopic lens system nor was it first employed in Galileo's telescope
two years earlier, as is popularly believed. The writings of two English mathematicians,
Leonard Digges and his son Thomas, scarcely admit of doubt that the telescope
was familiar to them. In Leonard Digges's treatise Pantometria,31 finished and
published by his son in 1571, occurs a passage which shows that they were well
acquainted with the effects of a combination of concave and convex lenses in magnifying
the image of a distant object.
But maruellouse are the conclusions that may be perfourmed by glasses concave
and convex of circulare and parabolicall fourmes, using for multiplication of
beames sometime the ayde of glasses transparent, which by [re]fraction should
unite or dissipate the images of figures presented by the reflection of other. By
these kinds of glasses, or rather frames of them, placed in due angles, ye may not
onely set out the proportion of an whole region, yea represent before your eye